Novel set of electrocardiographic left ventricular hypertrophy markers

La hipertrofia ventricular izquierda (HVI) induce cambios en las fases de despolarización y repolarización cardíaca. No obstante, pocos marcadores electrocardiográficos ncluyen parámetros de la repolarización en su diagnóstico. Objetivo de este estudio fue evaluar si la repolarización mejora el diagnóstico electrocardiográfico de la HVI. Material y Métodos: Se estudiamos los vectores QRS y T en el plano horizontal definido por las derivaciones precordiales V1 -V6 y el plano frontal definido por las derivaciones I-aVF en una serie de 40 pacientes con HVI y 34 sujetos control. Resultados: Los índices de HVI se construyeron como combinaciones de parámetros asociados a los vectores de despolarización y repolarización y su rendimiento se comparó con el rendimiento de los criterios de Sokolow-Lyon y Cornell. Los índices que incluyeron parámetros de repolarización mejoraron la sensibilidad de dichos criterios. Sobre los mismos, se construyeron estimativos a partir de medidas directas de amplitud del ECG, con el fin de obtener criterios de fácil medición en la práctica clínica. Para un 90% de especificidad, el mejor criterio, consistiendo en el voltaje de repolarización en la derivación V6 , produjo un 56% de sensibilidad, por encima del 30% de Sokolow-Lyon y el 40% de Cornell. Conclusiones: la repolarización contribuyó al diagnóstico electrocardiográfico de HVI y alentamos la búsqueda de nuevos índices en esta dirección.Left ventricular hypertrophy (LVH) induces changes in both depolarization and repolarization phases. However, little efforts were made to include repolarization features in its diagnosis. The aim of this study was to evaluate whether the repolarization improves ECG diagnosis of LVH. Methods: To do this, we studied the QRS and T vectors in the horizontal plane (HP) defined by the chest leads V1 -V6 and the frontal plane (PF) defined by the limb leads I-aVF in a series of 40 LVH patients and 34 control subjects. Results: LVH indices were constructed as combinations of parameters associated with depolarization and repolarization vectors and their performance was compared to the performance of Sokolow-Lyon and Cornell. Those indices, which included repolarization parameters, improved the sensitivity of these criteria. The latter were selected to construct estimates from direct measurements of ECG amplitudes, in order to obtain easy measurement criteria in the clinical practice. The best estimate, consisting of the repolarization voltage on lead V6 , produced a 56% sensitivity at 90% specificity, above Sokolow-Lyon (sensitivity 30%) and Cornell (sensitivity 40%). Conclusions: repolarization contributed to the electrocardiographic diagnosis of LVH and we encourage the search for new indices in this direction.Fil: Bonomini, Maria Paula. Universidad de Buenos Aires; ArgentinaFil: Ingallina, Fernando Juan. Universidad de Buenos Aires; ArgentinaFil: Barone, Valeria. Universidad de Buenos Aires; ArgentinaFil: Antonucci, Ricardo. Universidad de Buenos Aires; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderon; Argentin

The effect of breath pacing on task switching and working memory

The cortical and subcortical circuit regulating both cognition and cardiac autonomic interactions are already well established. This circuit has mainly been analyzed from cortex to heart. Thus, the heart rate variability (HRV) is usually considered a reflection of cortical activity. In this paper, we investigate whether HRV changes affect cortical activity. Short-term local autonomic changes were induced by three breathing strategies: spontaneous (Control), normal (NB) and slow paced breathing (SB). We measured the performance in two cognition domains: executive functions and processing speed. Breathing maneuvres produced three clearly differentiated autonomic states, which preconditioned the cognitive tasks. We found that the SB significantly increased the HRV low frequency (LF) power and lowered the power spectral density (PSD) peak to 0.1Hz. Meanwhile, executive function was assessed by the working memory test, whose accuracy significantly improved after SB, with no significant changes in the response times. Processing speed was assessed by a multitasking test. Consistently, the proportion of correct answers (success rate) was the only dependent variable affected by short-term and long-term breath pacing. These findings suggest that accuracy, and not timing of these two cognitive domains would benefit from short-term SB in this study population.Fil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Calvo, Mikel Val. Universidad Nacional de Educación a Distancia; España. Universidad Politécnica de Cartagena; EspañaFil: Morcillo, Alejandro Diaz. Universidad Politécnica de Cartagena; EspañaFil: Segovia, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vicente, Jose Manuel Ferrandez. Universidad Politécnica de Cartagena; EspañaFil: Fernández Jover, Eduardo. Universidad de Miguel Hernández; Españ

Modulation of spatial variance of ventricular repolarization after myocardial infarction

Myocardial infarction (MI) alters spatial features of thesurface electrocardiogram. Spatial variance of the T-wave (SVT )describes the interlead dispersion about a mean T-wave morphology. SVTwas linked to arrhythmiavulnerability and sudden cardiac death. In this work, we studied theevolution of SVT over the healing (MI7, up to 7 days after MI) and healed(MI60, from 60 days on post-MI) stages following MI. A control group(n=49) was compared to paired MI7 and MI60 groups (n=39). Fiverepresentative sets of frontal and precordial leads were analyzed: I-IIIII,V1-V2-V3, V4-V5-V6, aVF -V2-V5 and II-aVF -V5. SVT index signicantlyincreased at MI7 (p<0.05) in four out of ve sets and returned towardscontrol values at MI60 (p=NS) on patients without ventricular tachycardiaand/orventricular brillation (VT/VF). The preferential combination of ECG leadsresulted aVF -V2-V5, since it showed the strongest modulation over postMI time. In order totest whether such a modulation was maintained on the presence of VT=VF),recordings from VT=VF patients were also analyzed. SVT modulation waslost in the VT=VF group, signicantly increasing from controls at MI60(p<0.05) for all tested sets of leads. In conclusion, SVT modulation overMI7 and MI60 would signal a good recovery from MI, whereas lack of thismodulation could herald a VT=VF event.Fil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderon; Argentina. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderon; Argentina. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; Argentin

Spatial variance in the 12-lead ECG and mechanical dyssynchrony

Introduction: Electrical transmission disorders have a deleterious effect on cardiac depolarization, resulting in a disorganized ventricular contraction that reduces global mechanical efficiency; this mechanical dyssynchrony can be corrected by cardiac resynchronization therapy. However, despite adjustments in the electrical criteria selection of QRS for the recognition of mechanical dyssynchrony, a significant proportion of patients do not currently respond to this therapy. Purpose: To find if a new predictor of dyssynchrony, the electrocardiogram spatial variance, is a better marker of mechanical dyssynchrony than QRS duration. Methods: Forty-seven electrocardiograms and 47 strain (2D speckle tracking) echocardiograms were prospectively collected simultaneously in consecutive, non-selected patients; the left ventricular mechanical dispersion was measured in all the cases. The electrocardiographic analysis of variance was made with a digital superposition of the electrocardiographic leads and generates different indexes of variance of both QRS complex and repolarization phase. Results: ROC analysis probed that the best area under the curve (AUC) value correlated with left ventricular mechanical dispersion and was obtained combining several spatial variance markers (considering depolarization and repolarization spatial variance together; AUC = 0.97); the same analysis using the QRS duration versus mechanical dispersion showed a significantly lower AUC value (AUC = 0.64). Conclusion: Spatial variance combining depolarization and repolarization markers is a superior predictor of left ventricular mechanical dispersion than QRS duration.Fil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Villaroel Abrego, Hugo. Universidad del Salvador. Facultad de Medicina; ArgentinaFil: Garillo, Raúl. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; Argentin

Intracardiac Pressure - Volume Diagrams and Their Links with Thermodynamics

The main objective of this column is to historically connect the pressure–volume diagram (PVD) of the heat mechanical engines and that of the heart—a natural chemical engine—both types being generators of useful work.Fil: Valentinuzzi, Max E.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; ArgentinaFil: Arini, Pedro David. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Prediction of ventricular fibrillation based on the ST-segment

Based on some reported clinical data, we attempt to apply the allometric law for evaluating the probability of ventricular fibrillation when electrocardiographic ST-segment deviations are determined. The deviation is measured in millimeters at the standard calibration of 1mV = 10mm and the probability in percent. Using the equation VF P = δ + β (ST) in log-log representation, the fitting procedure produced the following overall coefficients: Average β = 1.11, with a maximum = 1.65 and a minimum = 0.78; Average δ = 0.83, with a maximum = 1.39 and a minimum = 0.41. For a 2mm ST-deviation, the full range of predicted ventricular fibrillation probability extended from about 6% at 1 month up to 47% at 4 years after the original cardiac event. These results, at least preliminarily, appear acceptable and still call for full clinical test. The model seems promising if other parameters were taken into account, such as cardiac enzyme concentration, ischemic or infarcted epicardial areas or ejection fraction. It is concluded, considering these results and a few references found in the literature, that the allometric model shows promising features in cardiology.Fil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Instituto de Ingeniería Biomédica; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad Maimónides; ArgentinaFil: Valentinuzzi, Max E.. Universidad de Buenos Aires. Instituto de Ingeniería Biomédica; Argentina32nd Annual International Conference of the IEEE EMBSArgentinaEl Instituto de Ingenieros Eléctricos y Electrónico

Inverse allometry: foundations for a bioinspired LVH-prediction model

Allometry, in general biology, measures the relative growth of a part in relation to the whole living organism. Left ventricular hypertrophy (LVH) is the heart adaptation to excessive load (systolic or diastolic) that leads to an increase in left ventricular mass, which in turn, raises the electrocardiographic voltages. If this mass increase followed an allometric law, then it would be possible to design a bioinspired model based on the allometric equation to predict LVH. In this work, we first investigated the validity of this hypothesis and then proposed an LVH marker based on the inverse allometry model. Based on clinical data, we compared the allometric behavior of three different ECG markers of LVH. To do this, the allometric fit AECG = δ + β(VM) relating left ventricular mass (estimated from echocardiographic data) and ECG amplitudes (expressed as the Cornell-Voltage, Sokolow and the ECG overall voltage indexes) were compared. Besides, sensitivity and specificity for each index were analyzed. The more sensitive the ECG criteria, the better the allometric fit. Finally, the Receiver Characteristic Curve (ROC) of an allometric model proposed here was computed. In conclusion: The allometric paradigm should be regarded as the way to design new and more sensitive ECG-based LVH markers.Fil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Ingallina, Fernando. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Barone, Valeria. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina5th International Work-conference on the Interplay between Natural and Artificial ComputationMallorcaEspañaInternational Work-Conference on the Interplay Between Natural and Artificial Computatio

2D ECG differences in frontal vs preferential planes inpatients referred for percutaneous transluminal coronary angioplasty

This work proposes a comparative study of a pair of electrocardiographic 2D representations: the frontalplane (FP) and a preferential plane (PP) obtained from ECG data. During depolarization and repolarization,main electrical vectors were analyzed and compared between healthy subjects and patients referred forpercutaneous transluminal coronary angioplasty (PTCA). Recordings were obtained at rest. Many patientsfrom the latter group presented normal ECGs, thus, the hypothesis to prove was that electrical axis in anyof the studied planes would effectively discriminate silent ischemia records from healthy ones. The FP wasconstructed with I and aVF leads, while the PP used the two first eigenvectors of the spatial correlationmatrix of the ECG. Although the depolarization and repolarization vectors from both groups resultednormal, those from the silent ischemia group appeared strongly biased to the left, closer to the limit ofthe normality range. This slight change originated a significant separation between health and disease inthe FP. Here, most of the parameters resulted highly informative, even those related to the depolarizationphase. The cardiac vector, integrating both depolarization and repolarization information, presentedthe highest performance (AUC = 0.89). Parameters in the PP, however, did not produce an acceptablediscrimination, except for the amplitude of the T-wave (AUC = 0.79). Additionally, the repolarizationorientation in the FP was the only marker that simultaneously discriminated three different groups ofpatients according to their occlusion sites (p < 0.0001). In conclusion: the FP offered a 2D representationgeneral enough to enable the separation of silent ischemia versus health populations while the PP didnot, due mainly to its individually optimized nature, failing to provide a unique referencial frame for allthe subjects.Fil: Bonomini, Maria Paula. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Corizzo Sebastián Javier. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; ArgentinaFil: Laguna, Pablo. Universidad de Zaragoza; España. Centro de Investigación Biomédica en Red; EspañaFil: Arini, Pedro David. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

Dynamic response of electrocardiographic indices during abrupt heart rate changes: comparison between young and middle-aged subjets

Abnormal modifications in ventricular repolarization dispersion (VRD) have been shown to constitute a substrate for malignant arrhythmias. In this work, we have induced abrupt heart rate (HR) changes to young and middle-aged healthy subjects through a Tilt-test and have analyzed the evolution of several VRD indices. Duration ones, based on electrocardiogram intervals; energy ones, developed through a Principal Components Analysis (PCA) in T-wave; and the morphology ones, extracted feature from an absolute T-wave. In both groups, results have shown significant decreases in early repolarization duration. These changes are responsible for the alterations in the total repolarization duration, because T-wave peak-to-end has not shown statistical significance. Moreover, we have found significant decreases in total, early and late repolarization energy, and in the T-wave amplitude. In another sense, we have observed that the repolarization energy obtained by PCA jointly with early T-wave slope and amplitude have been able to reflect VRD differences between young and middle-aged subjects. Finally, this work provides the range of values for VRD in normal conditions during abrupt HR changes. Outside this range, we could assume that it exists a cardiac risk.Fil: Teperino Marcos Javier. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; ArgentinaFil: Bonomini, Maria Paula. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Cruces, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina8th International Conference on Bio-Inspired Systems and Signal ProcessingLisbonPortugalInstitute for Systems and Technologies of Information, Control and Communicatio